The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
The motorization assemblies for aircrafts generally include a nacelle forming a generally circular outer shell, comprising in the interior a turbojet engine disposed along the longitudinal axis of this nacelle. The turbojet engine receives fresh air coming from the upstream or front side, and rejects from the downstream or back side the hot gases resulting from the combustion of the fuel, which provide some thrust.
The bypass turbojet engines present, around this turbojet engine, fan blades generating an important secondary flow of cold air along an annular flow path passing between the engine and the nacelle, which adds a high thrust.
Some nacelles include a thrust reverser system which closes at least partially the annular flow path of cold air, and rejects the secondary flow forward in order to generate a braking thrust of the aircraft.
A known type of thrust reverser, presented in particular in the document FR-A1-2758161, includes rear movable cowls called “Trans-cowl,” sliding axially rearward under the effect of cylinders by deploying flaps in the annular flow path in order to close for the most part this flow path. The flaps return the cold air flow radially outward by passing through cascade vanes uncovered by the movable cowls during their sliding movements, comprising blades which direct this flow forward.
Furthermore, some nacelles include a secondary rear nozzle called “Variable Fan Nozzle” (VFN), providing a secondary variable flow thanks to a translational movement of this nozzle which is connected to the movable cowls of the thrust reverser by guide means allowing an axial movement of the control system.
An actuation system known to the thrust reverser as well as to the variable secondary nozzle, include cylinders fixed on one side to the front fixed structure and on the other side to the secondary nozzle disposed at the rear, these cylinders pass through the entire structure of the movable cowls of the thrust reverser located axially between these two portions. The nacelle also includes two independent controlled locks, a fixed lock linking the front structure to the cowls, and a movable lock linking these cowls to the secondary nozzle.
By actuating the cylinders rearward, only a decrease of the secondary nozzle is obtained if the movable lock is open and the fixed lock is closed, and a deployment of the thrust reverser together with the nozzle if, conversely, the fixed lock is open and the movable lock is closed.
A problem which arises with this actuation system is that, for controlling the movable cowls, the axial thrust reversers developed by the cylinders are directly applied to the secondary nozzle disposed rearward, which then transmits these forces forward to the movable cowls by the movable lock. It is then necessary to size the secondary nozzle in order to transmit these constraints, thereby forcing to provide for additional masses.